Manufacture of arylnaphthylamines



Patented Sept. 1, 1936 PATENT" OFFICE MANUFACTURE OF ARYLNAPH'IHYLAlVHNES Frederick H. Kranz, Buffalo, N. Y assignor to National Aniline and Chemical Company, Inc., New York, N. Y., a corporation'of New York No Drawing. Application November 22, 1933,

Serial No. 699,135

5 Claims. (or. 260-128 This application relates to the preparation of di(arylamino) -naphthalenes. It is especially dirooted to the production of 1,3-di(arylamino) naphthalene-sulfonates from primary and secondary alphanaphthylamines containing a sulfonate group in meta-position to the amino group.

It is known that 1-,3-di(ary1amino) -naphth alene-sulfonates may be prepared by heating arylamines and arylamine hydrochlorides with 1,3- naphthylamineesulfonates at temperatures above 150 C. Theamino groups of the two compounds react to liberate ammonia and form an arylaminonaphthalene linkage. The amine or amine salt also reacts with the sulfonate group with the liberation of sulfur dioxide and water to form a second arylaminonaphthalene linkage. The reaction may be represented as follows:

Prior to the present invention it has been supposed that the above high temperatures were essential for the reaction of the sulfonate group with the amine and that at lower temperatures the monoarylamino-naphthaleneesulfonate would be produced by reaction: of the two amines, the sulfonate group being unafieoted.

I have found that by maintaining suitable reaction conditions not only may the 1,3-di(arylamino) -naphthalenes be formed at temperatures lower than 150 C. but that a better yield and quality of product may be produced at the lower temperatures; ,In effecting the reaction at high temperatures tarry "by-products are formed. These by-products not only reduce the yield of the desired product by causing a portion of the initial'materials to .beused up but are inthem selves objectionable ingredients in that they ad- 'versely afiect the color, purity, and .solubility of the product and, since the product is largely employed as a dye intermediate, render-result ant dyes and dyeings less perfect than otherwise obtainable u'nl'ess'in the purification of the product especial care-is taken to remove these byproducts.

In accordance with my invention a l-aminonaphthalene-3-sulfonate or l-arylaminonaphthalene-3-sulfonate is gradually added over a. sufiiciently extended period of time to a fluid mixture of a" primary arylamine or arylamine salt, so-that the reaction mixture is maintained substantially throughout the reaction period in a fluid condition. By operating in this manner,

theagitation of the reaction massis facilitated, maintenance; of 'uniform' temperature conditions throughout the reaction mass is'made feasible,

and a temperature not exceeding 135 C. is efiother1-hand, the time required for treatment graduallyincreases as'the temperatureis diminished. Temperatures as low as 0., however, have been found tobe satisfactory. In gen- .eral reduction in temperature results'in higher viscosity of the reaction mixturecausing more diflicult stirring. The employment of too low a temperature will be reflected in high power requirements and reduced of the product.

Inefiecting the preparation of di(arylamino) uniformity. and quality naphthalene-sulfonates in accordance with the present invention, it is, desirable that a minimum amount ofwater be present and also it is desirable that the initial materials contain as little 'aspossible-10f sodium'chloride, preferably less than 1% by weight. This is more important when the sodium salts of the sulfonic'acids are employed than when the sulfonic. acids themselves are employedisincerin the former case sodium chloride willbe formed as a product of the reaction and thus increase the sodium chloride content of the reaction mixture.

My invention is applicable-in particular to the preparation of: di(arylamino)-naphthalene-sul fonates from 1-amino-naphtha1ene-3,8-disulfonates by reaction with primary aromatic amines, or their salts,'-'-e. g; the hydrohalides,.'-

such as hydrochlorides;hydrobromides, and hydroiodides-, benzoates, and sulfates. These di- (arylamino) -naphthalene-sulfonates may be rep- 1 resented by the following iormula:

MeOaIS Hu -R.

wherein R1 and R2 may be the same or difierent aryl radicals constituting the residue of an arcnaphthalene 3,5,8-trisulfonates. the sulfonate group in the-3" position is substimatic amine and containing or not containingfurther substituents; examples are the phenyl-,

tolyl-, xylyl-, and naphthyl-radicals; and Me represents hydrogen or an alkali-metal.

The invention is similarly applicable to the preparation of diarylaminonaphthalenes generally from naphthalene-sulfonates containing the -NH- group in alpha-position and ajsulfonate group in meta-position in respect thereto,--for example, the preparation of diarylaminonaphthalenes .by reaction of primary aromatic amines or their salts upon 1-aminonaphthalene-3-mono tion of primary aromatic amines or their salts upon l-arylaminonaphthalene-3,8-disulfonates,

1-aminonaphthalene-3,5-disulfonates, l-arylami l-aminonaph- I nonaphthalene-3,5-disulfonates,

thalene-3,5,8-trisu1fonates, and l-arylaminotuted by an 'arylamino-group, the other sulfonate grOups,'when present, remaining. f 5 The following specific example is further illustrative of the invention herein described, the parts A yield of about U V amino) naphthalenegB-sulfonic acid having the followingprobable formula is obtained; 7

being by weight: 7 Emample.-A mixture of 495 parts of aniline and parts of hydrochloric acid, 20 B. (31%), is heated to a temperature of 130 C. ataboutiatmospheric pressure, thereby distilling ofi' a portion of the aniline'and water present. The resultant hot-mixture of aniline and aniline hydrochloride is fluid but possesses a low water content, that is' 2 percent or less-of water. To this fluid mixture there is added 7.5 parts of dry l-amin'onaphthalene 3 ,8 -monosodium disulfonatedihydrate at about 15 minute intervals until parts of the sulfonate has been added. In this-manner, the fluid condition of the reaction mixture is retained throughout the reaction period; provided the temperature ismaintained. The addition of the sulfonat'e'requires about 3 hours.

During this addition, and for a period of .24 hours'th'ereafter, the mixture is maintained at a temperature between 128* and- 132 C. Lower tempera- ;tures may be employed for the fusion, in which case a longer fusion period should be employed;

'fOr example, at Crthe above reaction proceeds to completion in a fusion period of about 36 hoursinstead of 24 hours.

The purification or isolation may be efiected in any well-known manner, for example, by adding.

alcohol whereby, since the free-acid is almost insoluble in alcohol, the soluble impurities are extracted, p

90 parts of purified :1,3-di(aryl- In each case The product formed by the above process is obtained not only in larger yields but much freer from tarry by-products than thatprepared by formerly known methods, containing only 0'-2% impurities, and is therefore of better color and solubility. Furthermore, since these compounds.

are of particular application as dye intermediates,

better dyes and dyeings are obtainable therewith.

I Claim} 1; In the preparation of a di(arlyamino) '-l "naphthalene, the method which comprises heating a'mixtureof aipr'imary arylamine and an inorganic acid addition salt thereof to a temperature sufficient to maintain the mixture in a stirrablelcondition but not above 135 C. and gradually'adding to the mixture, while maintaining the V elevated'temperature, a member of the group consisting of l-aminonaphthalenes and l-arylaminonaphthalenes, containing'a sulfonate group in meta-position to the aminoor imino-group and regulating the addition'thereof' so as to maintain the reaction mixture in a fluid conditj n. I E

2. The method of preparing a i1',3-diarylaminonaphthalene 8-sulfonate, which comprises heating amixture of an arylamine and its hydrochloride to an elevated temperature between 120 and 135 C. and gradually adding thereto, While maintaining the elevated temperature, a l-naphthylamine-3,8-disulfonate, and continuing the heating until the reaction to the 1,3-diarylaminonaphthalene-8-sulfoinate is substantially comgradually-adding thereto over a-period of between three and four hours, whilemaintaining. the elenot more than 1' per cent of sodium fchloride,

regulatingthe additionof the naphthylamine so as to maintain the reaction mixture in'a fluid condition throughout substantially the entire period, and continuing the heating at about C. for an additional twenty-four hours.

4. In the preparation of a di(arylam-ino) -naph- I thalene by heating a primary arylamine or'inorganic acid addition salt thereof .with a sulfonate of the group consisting of l-aminonaph- 'thalenes and '1-arylaminonaphthalenes, containing a' sulfonate group in meta-position to the aminoor imino-group, the improvement-which:

comprises gradually adding the sulfonate to the primary arylamine or salt thereof, maintained provement which comprises gradually adding the sulfonate to the primary arylamine hydrochloride, maintained at a temperature between 120 and C. y

' 7 FREDERICK H. KRANZ; 

